Arrangement for locating rollers with an increased rotatory resistance in a roller way

ABSTRACT

In order to be able to locate stuck rollers of a roller way as early as possible, with longer operational interruptions being avoided and the demounting of constructional parts of the roller way being not necessary, an arrangement for this purpose includes a supporting body which is movable along the roller way and carries a frictional head. The frictional head is pressable against the surface areas of subsequently arranged rollers. Means are provided for recording and measuring a difference between the velocity of the supporting body with which the latter is moved along the roller way and the velocity of the frictional head getting into contact with a roller.

BACKGROUND OF THE INVENTION

The invention relates to an arrangement for locating rollers with anincreased rotatory resistance in a roller way, in particular strandguiding rollers in a continuous casting plant.

In continuous casting plants, the strand is guided between twooppositely arranged roller ways and cooled, after having left thecontinuous casting mould, i.e at least over a distance corresponding tothe length of the liquid phase of the strand. The rollers of theseroller ways have relatively small diameters and are arranged as closelyadjacent as possible in order to effectively prevent bulging of thestrand. The rollers are held, and surrounded, by a framework. Due to thecompact construction of the rollers and the framework, the rollers aredifficult to reach from outside.

Due to the high thermal stress of the rollers by the red-hot strandhaving a liquid core as well as by the cooling water, a failure of theroller bearings may occur so that individual rollers of the roller wayswill get stuck or are difficult to rotate. Not only is thisdisadvantageous to the quality of the strand, but it also constitutes adanger to the entire plant, since the strand will drag along the stuckrollers, thus possibly leading to a rupture of the thin strand skin and,accordingly, to a strand breakthrough.

SUMMARY OF THE INVENTION

The present invention aims at detecting as early as possible rollersthat have become stuck. This should be possible without longinterruptions in operation. In particular the detection of stuck rollersis to be feasible without the necessity of demounting structural partsof the roller way.

This object is achieved according to the invention by a supporting bodywhich is movable along the roller way and carries a frictional head,which frictional head is pressable against the surface areas ofsubsequently arranged rollers, and an arrangement is provided forrecording and measuring a difference in the velocity of the supportingbody with which it is moved along the roller way and the velocity ofthat part of the frictional head which comes into contact with a roller.The supporting body can be coupled to the starter bar and moved with thestarter bar between the roller ways, which constitutes routine work incontinuous casting plants, requiring only very little time.

Advantageously, the supporting body comprises at least one surface thatis in contact with the rollers of one roller way, and the frictionalhead is resiliently mounted on the supporting body, thereby beingmovable from a position projecting beyond the surface into a position inalignment with the surface, when coming into contact with a roller.

According to a preferred embodiment, the frictional head is designed asa frictional wheel, the frictional wheel being pressable with itscircumference against the surface area of a roller, and an arrangementis provided which indicates a rotatory movement of the frictional wheel.

Suitably, the frictional wheel is mounted on a pivot arm arranged on thesupporting body, wherein the pivot axis of the pivot arm is directedparallel to the axis of the frictional wheel and the pivot arm ismovable by spring means towards a stop delimiting its movement towardsthe rollers.

According to another advantageous embodiment, the frictional wheel ismounted to be slideable along a guide and is pressable, by spring means,against a stop delimiting its movement towards the rollers.

It is advantageous, if the frictional wheel serves as drive for a camdisk whose cams initiate signals upon rotatory movement, preferably byclosing an electric contact.

The frictional wheel suitably may also be connected with a tachometergenerator.

According to a further preferred embodiment, the frictional head isdesigned as a piston which is pressable against the surface area of aroller at an approximately right angle to the roller way and which ismounted on the supporting body so as to be displaceable in the movingdirection of the supporting body along guides, wherein a means forrecording and measuring a relative movement of the piston relative tothe supporting body in the moving direction of the supporting body isprovided.

Suitably, this piston in this embodiment is mounted on a car that isdisplaceable in the moving direction of the supporting body, which carpreferably is displaceable by means of longitudinal guides on rollersprovided at the supporting body, wherein distance indicators, such as amagnetic coil with an iron core, or electric contacts, are provided onthe car and on the supporting body for recording a relative movementbetween the car and the supporting body.

Preferably, the surface of the supporting body that is in contact withthe roller way is formed by an elastically deformable steel strip.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of threeembodiments and with reference to the accompanying drawings, wherein:

FIG. 1 is a side view of an arrangement according to the invention in afirst embodiment;

FIG. 2 is a section along line II--II of FIG. 1;

FIG. 3 is a detail of FIG. 1 on an enlarged scale;

FIG. 4 is a section along line IV--IV of FIG. 3 according to thisembodiment;

FIG. 5 shows a further embodiment in an illustration analogous to FIG.4;

FIG. 6 represents a third embodiment sectioned perpendicularly to theroller axes of the roller ways;

FIG. 7 illustrates a section along line VII--VII of FIG. 6; and

FIG. 8 is a section along line VIII--VIII of FIG. 7.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Between roller ways 1 and 2, comprising rollers 3, of a strand guide ofa continuous casting plant, an arrangement 4 for locating stuck rollersis inserted. It is connected with a dummy bar 6 by means of a coupling5. The arrangement comprises a supporting body 7 which is formed of twooppositely arranged, elastically deformable steel strips 8, 8' that arepressed apart by spring cups 9, 9' arranged one behind the other.Thereby the steel strips 8, 8' come into contact with the rollers 3 ofthe roller ways 1 and 2. By pulling or pushing through the supportingbody 7, the rollers 3 that have not become stuck are set in rotation.Instead of the spring cups 9, 9', also hydraulically or pneumaticallyactuated pistons or the like, which press the steel strips 8, 8' apart,could be provided.

The supporting body 7 is articulately connected with the coupling 5 viathe middle spring cup 9' by rods 10 and laterally arranged longitudinalbeams 11. On one of the steel strips 8, a console 12 is riveted to whicha pivot arm 13 is hinged, the pivot axis 14 extending parallel to theaxes 15 of the rollers 3 of the strand guideways. The pivot arm isconstantly moved by means of a spring 16 in the direction of arrow 16',i.e. towards the roller ways. A stop 17 for the pivot arm 13 takes carethat the pivot arm will not be pressed too much towards the rollers 3.On the free end of the pivot arm 13 a frictional head, which is designedas a frictional wheel 18, is rotatably mounted. The axis 19 about whichthe frictional wheel 18 is rotatable is directed parallel to the pivotaxis 14 of the pivot arm. A cam disk 20 is coaxially fastened to thefrictional wheel 18, the cams 21 of the cam disk closing an electriccontact 22 in the event of a rotatory movement of the frictional wheel18.

The arrangement functions in the following manner: The steel strips 8,8', which are spread by the spring cups 9, 9' come into contact with therollers 3 of the roller ways 1, 2, wherein, after having overcome thebearing play of the rollers 3, the latter are turned, provided they arenot stuck, due to the pulling of the arrangement 4 between the rollerways 1, 2. The circumferential speed of the rollers corresponds to thetransporting speed of the supporting body 7. The frictional wheel 18,which is resiliently pressed against the rollers 3, will not perform arotary movement relative to the supporting body 7 when in contact withthe rollers, if the rollers rotate, since the circumference of thefrictional wheel 18 is moved so as to pass by the rollers 3 at thetransporting speed of the supporting body 7. The frictional wheel 18merely is pushed back from its position projecting beyond the steelstrip 8, until the circumference of the frictional wheel 18 is inalignment with the steel strip 8, which is in contact with the surfaceareas of the rollers 3. If the frictional wheel comes into contact witha stuck roller 3 or with a roller 3 that rotates only withdifficulty--with such a roller there is a sliding movement between thecontacting surface 23 of the steel strip 8 and the surface of theroller--the frictional wheel 18 is set in rotation and the electriccontact 22 is closed. The closing of the electric contact is used forconducting a signal to a recording means, which is accommodated forinstance in a box 24 mounted at the arrangement 4. With the help of awireless transmission of the signals, it would also be possible toarrange the recording means for instance on a stationary control stand,independently of the supporting body 7. If the recording means, inaddition to each signal, also records the respective position of thesupporting body within the roller ways, the position of the stuck rollercan be immediately determined. The position of a stuck roller can berecorded in connection with an axially movable tracing pin 25 projectingbeyond the steel strip, which tracing pin is pushed down by each strandguiding roller 3 is passes, thus initiating a signal. Instead of by theelectric contact, signals can be triggered also in other manners, forinstance pneumatically.

For checking the rollers 3 of the lower roller way 2, the arrangement 4is turned about its longitudinal axis by 180° and again moved betweenthe roller ways. It is also possible to provide a frictional wheel 18 onboth steel strips 8, 8' so that the location of stuck rollers ispossible in one operational step at both roller ways 1, 2.

In the embodiment illustrated in FIG. 5 the frictional wheel 18 isdisplaceable along a guide 26 which is directed perpendicularly to thecontact face 23 of the steel strip 8. The guide is designed as a pistonsliding at a cylinder 27 which is fastened to the steel strip 8. Aspring 28 serves for pressing the frictional wheel 18 against the strandguiding rollers, a stop 17 again limiting the movement towards therollers 3. A rotatory movement of the frictional wheel 18 is transferredto a tachometer generator 29 which initiates a signal to a recordingdevice, according to the rotatory movement of the frictional wheel.

The perpendicular movement of the frictional wheel 18 inclusive of thecasing and the piston 26, which occurs every time the arrangement ispressed down by a strand guiding roller, can be used in the same way asthe movement of an axially movable tracing pin 25 in the form of anoutput signal for recording the position of the roller in question.

In the embodiment illustrated in FIGS. 6 to 8 the frictional head isdesigned as a piston 30 which is mounted so as to be displaceableapproximately perpendicular to the contact face 23 of the steel strip 8and is pressed outwardly by a spring 31, beyond the contact face 23. Thepiston 30 is mounted on a car 33 which is displaceable in the movingdirection of the supporting body 7, which direction is indicated by thedouble arrow 32. The car 33 comprises longitudinal guides 34, which arein contact with the rollers 35 arranged on the supporting body 7. Forindicating a relative movement of the piston 30 relative to thesupporting body 7 in the moving direction of the supporting body 7--sucha relative movement occurs when the piston comes into contact with aroller 3 that has got stuck or is difficult to rotate--an inductivedistance indicator 36 is provided, as is illustrated in FIG. 6 on theleft-hand side. In this case, an iron core 37 mounted in the car 33moves into a magnetic coil 38 that is fastened to the supporting body 7.Instead of the inductive distance indicator, it is also possible toprovide a distance indicator that is designed as an electric contact 39,as is illustrated in FIG. 6 on the right-hand side. The car 33 is heldin the mid-position, as long as the piston 30 does not carry out arelative movement relative to the supporting body 7 in the longitudinaldirection of the same, due to a stuck roller 3, by means of two springs40, each of which leans against the car 33 and against consoles 41 whichare fastened on the steel strip 8.

What we claim is:
 1. An arrangement for locating rollers with anincreased rotatory resistance in a roller way such as strand guidingrollers in a continuous casting plant, which arrangement comprisesasupporting body movable along said roller way, a frictional headprovided on said supporting body and pressable to the surface area ofsubsequently arranged rollers, means for moving said supporting bodyalong said roller way, and means for indicating and recording adifference between the velocity of said supporting body with which saidsupporting body moves along said roller way and the velocity of thatpart of said frictional head which comes into contact with a roller. 2.An arrangement as set forth in claim 1, wherein said supporting bodycomprises at least one contact face contacting the rollers of a rollerway, and said frictional head is resiliently mounted on said supportingbody, said frictional head, when in contact with a roller, being movablefrom a position projecting beyond said contact face into a position inalignment with said contact face.
 3. An arrangement as set forth inclaim 1, wherein said frictional head is designed as a frictional wheel,said frictional wheel being pressable with its circumference against thesurface area of a roller, and further comprising means for indicating arotatory movement of said frictional wheel.
 4. An arrangement as setforth in claim 3, further comprising a pivot arm mounted on saidsupporting body for supporting said frictional wheel, the pivot axis ofsaid pivot arm being directed parallel to the axis of said frictionalwheel, a stop for delimiting the movement of said pivot arm towards saidrollers, and spring means for moving said pivot arm towards said stop.5. An arrangement as set forth in claim 3, further comprising a guidefor mounting said frictional wheel so as to be slideable along saidguide, a stop for delimiting the movement of said frictional wheeltowards said rollers, and pressing spring means for pressing saidfrictional wheel against said stop.
 6. An arrangement as set forth inclaim 3 or 4, further comprising a cam disk including cams, and whereinsaid frictional wheel serves for driving said cam disk, said camsinitiating signals upon rotatory movement of said frictional wheel. 7.An arrangement as set forth in claim 3 or 4, further comprising a camdisk including cams, and wherein said frictional wheel serves fordriving said cam disk, said cams closing an electric contact uponrotatory movement of said frictional wheel.
 8. An arrangement as setforth in claim 5, further comprising a tachometer generator connected tosaid frictional wheel.
 9. An arrangement as set forth in claim 1,wherein said frictional head is designed as a piston that is pressableagainst the surface area of a roller approximately at a right angle tothe roller way, which arrangement further comprises guides for mountingsaid piston on said supporting body so as to be displaceable along saidguides in the moving direction of said supporting body, and means forindicating and recording a relative movement of said piston relative tosaid supporting body in the moving direction of said supporting body.10. An arrangement as set forth in claim 9, further comprising a cardisplaceable in the moving direction of said supporting body, saidpiston being mounted on said car.
 11. An arrangement as set forth inclaim 10, further comprising longitudinal guides and supporting bodyrollers provided on said supporting body for displacing said car alongsaid longitudinal guides on said supporting body rollers.
 12. Anarrangement as set forth in claim 10, wherein said means for indicatingand recording comprising distance indicators provided on said car and onsaid supporting body for indicating a relative movement between said carand said supporting body.
 13. An arrangement as set forth in claim 12,wherein said distance indicators are designed as a magnetic coilincluding an iron core.
 14. An arrangement as set forth in claim 12,wherein said distance indicators are designed as electric contacts. 15.An arrangement as set forth in claim 2, wherein said at least onecontact face of said supporting body is formed by an elasticallydeformable steel strip.